This invention pertains to the art of blood pumps, and more particularly to rotary blood pumps. The invention is applicable to a fluid motor driven pump that may be implanted in a body cavity and will be described with particular reference thereto. However, it will be appreciated that the invention has broader applications and may be employed in related environments and applications.
Available rotary blood pumps, although varying in different aspects of their design, typically have one common feature. Specifically, most known rotary blood pumps employ an electric motor as the prime mover for the device. Although deemed to be reliable from an operational standpoint, electric motors are undesirable for other reasons. For example, the size of an electric motor is a primary drawback. When faced with scaling down or miniaturizing components due to the limited space available in the body cavity, it is believed that other smaller drive arrangements would be equally suitable.
Yet another deficiency associated with electric motors is the need to bring electricity into the body. Although precautions are taken and believed to adapt electric motors to internal use, these safeguards can be eliminated if the reason for the safeguards is itself eliminated; namely, the electric motor.
Due to the nature of electric motors, heat is produced during operation of the motor and it becomes necessary to cool the motor. Typically, fluid is continuously circulated around the motor and the heat transferred thereto resulting in a net cooling of the blood pump. Many of these rotary blood pumps thus supply sealing or cooling fluid to the pump assembly for just such a purpose.
As a result of the conventional use of electric motors and the associated need to cool the motor, plural supply lines must also enter the body cavity. This results in a complex array of lines that each control different operational aspects of the pump. Thus the need to reduce the number of skin penetrations becomes another consideration when evaluating the continued use of an electric motor as the prime mover for a blood pump.
It has been deemed desirable to maintain all of the above benefits of a rotary blood pump having an electric motor and overcome various deficiencies in the prior arrangements.